Stitch-forming mechanism for sewing-machines



J. R. MOFFT T.

STITCH FORMING MECHANISM'FOR SEWING MACHINES. APPucArxoN HLED MAR. 29,191s.

1 ,366,476. Patented Jan. 25, 1921.

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A l Clftotnn J. R. MOFFATT. STlTCH FORMING MECHANISM FOR SEWINGMACHINES.

APPLICATION HLED 11.29. 191s. 1,366,476. Patented Jan. 25, 1921.

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J. 8.MOFFAIT. STITCH FoIIMING MECHANISM FoII SEWING MACHINES.APPLICATION FILED MAR. 29. |918.

1,366,476. Patented Jan. 25,1921.

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STITCH FORMINGME'CHANISM FOR SEWING MACHINES. APPLICATION' man ML2-9.lala.

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J. R. MOFFATT. STITCH FoRMlNG MECH/msm Foa sfwmc MACHINES.

APPLICATIl-)N FILED IAR-29. |918. Patenm Jan. 25. 1921i 5 ,SHEET S-SHEEY5.

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UNITED srArg vlgivlllilhl'fvOFFICE.

JAMES R. MOFFATT, 0F CHICAGO, ILLINOIS, ASSIGNOR TO UNION SPECIAL MACHINCOMPANY, or'cnrcseo, rumor S, A CORPORATION 0F ILLINOIS.

STITCH-FORMING ISM FOR SEWIN G-MACHIN ES.

Specification of Letterslatent.

Patented Jan. 25, 41921.

Application led March 29, 1918. Serial No. 225,488.

T o all fr0/lam t may concern.'

Be it known that I, JAMES R. Mor-Farr, a citizen of the United States,residingat Chicago, in the county of Cook, State of Illinois, haveinvented certain new and useful Improvements in Stitch-Forming Mechanismfor Sewing-Machines, of which the following is a description, referencebeing had to the accompanying drawing' and to the figures of referencemarked thereon.

The invention relates to new and useful improvements in stitch formingmechanisms for sewing machines and more particularly to a stitch formingmechanism having` devices adapted to join the meeting edges of fabricsections and for covering the meeting edges thereof.

An object of the invention is to provide a stitch forming mechanism ofthe above character wherein the fabric sections being stitched aresupported by a cylindrical work support and wherein said fabric sectionsare fed onto the work support underneath the overhanging arm carryingthe stitching elements located above the work support, and wherein saidstitching elements are arranged so as to provide ample clearance spaceunderneath the arm for the handling of the fabric sections.

A further object of the invention is to provide a machine of the abovecharacter wherein the edges of the fabric sections to be' joined aretrimmedprior to the stitching of theV same by horizontally,-disposedtrimming' devices4 and wherein the lines of stitching are joined byacross thread which covers the upper surface of the meeting edges of thefabric sections. Y

Astill further object of the invention is to provide a stitching.mechanism of the above character wherein the movable trimming blade andthe thread hook for laying the cross thread, are both operated from asingle eccentric.

These and other objects will in part be obvious and will in part behereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of theinvention Figure l is a side view of a machine embodying my invention;

Fig. 2is a front elevation of the parts located at the front end of themachine. showing the work supporting cylinder in end view;

Fig. 3 is an enlarged view of the front end of the machine as viewedfrom the same side as in Fig. i with the work support broken away toshow the looper and the trimming lever broken away to show the crossthread laying' mechanism;

'F ig. 4 is an enlarged view of the opposlte side of the machine, withthe work support broken away to show the looper and a part of thefeeding mechanism, the presser foot also being in section;

Fig. 5 is a sectional view on the line 5-5 of Fig. si, the tension forthe cross thread being omitted;

Fig. G is a sectional view on the line 6--6 of Fig. l; and

Fig. 7 is a view showing the relation of the fabric sections to thestitching and covering threads. I

The invention is especially adapted for a sewing machine having astandard carrying a cylindrical work support and an overhanging armwhich isrparallel with and overhangs the work support. The fabricsections to be joined are fed onto the work support and in a directionparallel with the longitudinal axis thereof. The edges to be joined areturned out of the plane of the fabric sections and are trimmed byhorizontally disposed trimming members, after which they are preferablyslightly overlapped and they are then joined by a three needle stitchingmechanism, the center needle only, passing through the overlapped fabricsections. Coperating with the needles beneath the work support, is asingle looper and cooperating with the needles above the work support,is a thread hook and thread finger, which lays a cross thread in loopsfor the needles to enter. Thus the cross thread joins the lines ofstitching and covers the edges of the joined fabric sections. The stitchforming elements are all operated from a cross shaft at right angles tothe work support. The movable blade of the trimming mechanism and thethread hook are both operated from a single eccentric on the cross shaftand the connections between this eccentric and the hook and trimmingblade are so disposed as to givel ample Yclearance room for the handlingof the fabric sections underneath the work supporting arm. Y

Referring more in detail -to the drawings, I have shown my invention asapplied to a machine having a supporting basel, carrying a standard 2,on which is mounted an overhaiiging arm' 3. Projecting from the standard2 is a cylindrical work supporting arm or bed t. This worksupporting armis located directly underneath the overhanging arin and is paralleltherewitl'i.V Mounted to reciprocate in the outer end of the overhangingarm 3 is a needle bar 5 carrying three needles 6, 7 and 3.V This needlebar is reciprocated by a needle lever 9 which connected to a link 10,which in turn is con-- nected to the needle bar. The needle lever 9 isoscillated b y suitable means from 'the main shaft indicated in dottedlines at 11 overhan-Uino arm.

jfroin (the extreme in Fig. 1 of the drawings. This main shaft lies in apla-ne at right angles to the longitudinal axis of the work support.

Coperating with the three needles beneath the work support, isV athreaded looper 12. This loopei' is carried by a looper supporting shaft13, which is also operated by suitable connections with the main shaft1.1. The fabric sections are fed onto the work supporting arm and inadirection parallel with its longitudinal axis by a feeding mechanismwhich includes feed dogs 11i.

VThese feed dogs have their teeth arranged so as to feed the materialonto the work supporting arm and said feed dogs are operated by suitableconnections with t-he main shaft 11. Machines of this typer are wellknown in the art and it isnot'thc'ught that furthe-r detail descriptionthereof is necessary.

The material is hel-d on the work support by a presser foot 15. Thispresser foot is carried by a presser bar 16 mounted in the This presserbar 16 is connected by a pin 1Ga to a collar 16" on the presser guide`bar 16C. The presser bar is forced downwardly by a flatl spring 17, andwhich bears against a pin 19 fixed to the guide bar 16C.V Thepi'esserbar is raised by ka lever 18 which engages the pin 19 on thepresser guide bar. The presser foot is formed with a. guiding slot 20`which leads front end thereof in the line of feed and terminates justVin front of the needle opening 21, whichreceives the three needles G, 7and 3. Mounted in a re- Vcesspii'i Vthe presser foot is a 'fixedtrimming blade 22. Coperating with this fixed trimming bladel is amovable trimming blade 23.

Y Said movable trimming blade is carried by a lever 24. Y At the end ofthe lever 24 is a vertically adjustable block 21a to which the blade 23'is clamped. The inner end'of the Vfixed blade 22 preferably terminatesat the side wall of the guiding slot'20, while Vthe movable blade 23moves across the Guiding z: C Y

shown diagranmiatieally in Fig. 7 of the drawings. In this igurerof thedrawings, I have indicated the fabric sections at F and F', the needlethreads for the needles 6, T

and 8 respectively, at 6, 7 and 8, the looper thread at Z and the crosstl-iread at c. Tt will' be noted that the fabric sections are soVdisposed that the central needle 7 passes through the overlapped edges,while the needle G passes at one side of the overlapped edges and theneedle 8 on the other side thereof. The cross thread c and loopei'thread Z cover the edges ofthe oined fabric sections.

The lever 2ak is mounted to swing about a guide bar 26,.V which in turnis mountedrin the overhanging. arm and is connected to an arm 27projecting from the presser foot.

Said lever 24 has a forked bearing and the arm 27 extends between theVmembers of the fork. This. connection holdsk the lever from sidewisemovement on. the bar 2G. A arm 27'is Vconnected'to the bar 26 by a .setscrew 2S. The lever 24 is not adinet-able sidewise and the movabletrimming blade is adjusted vertically by shifting the block 2111.Preferably formed integral with the arm of the lever carrying thetrimmer blade 23, is an aim 29 which serves to oscillate the lever. Thisarm 29 carries a ball stud 30v to which a link 31 isattached. Ti elink31 in turn is connected to a. lever 32, which is fulcrumbed at 33 on theoverhanging. arm. Mounted in the forward end of the overh-a-nging arm isa cross shaft-3t This cross shaft 34 cari'ies an upwardly extending arm35. Y Pivot'ed to this Vupwardly,extendingVV arm e5 a ecris@ iink 37.saiaiinie in @um is pivoted at 38 tothe lever 32. The cross shaft 34: isoperated by a link 39 which is pivoted at etO'to the arm 35 on Vthecross shaft 34. The other end of the link 39 is pivoted to a leveir41,which is fulcru-med at vl2 on a lug 43 carried bythe standard.

The lower end of the lever l1 is pivote'dat la te an eccentric strap 45,which cooperates Vwith an eccentric 461.011 the mainshaftv11.

As the main shaft rotates, the eccentric #16 will oscillate Ythe leverHand through. the vlink 39 oscillatesvthe cross shaft 3V and through thelink 31V oscillate the lever 2st4 carrying the. movable. trimmer blade23.

The cross thread indicated at c in the Y dra-wings is laid inloop form`.for the needles by a thread hook a7 and a cooperating thread finger4:8. The hook 47 is carried by a lever 49 which is mounted to turn aboutthe presser bar i6 as an axis. Said hook l? has an upwardly extendingshank 50 which is mounted in the outer end of one arm of the lever 49.The other arm of the lever 49 is pivoted at l to a link 52.A Thelink 52is in turn pivoted to a downwardly extending arm 58 carried by the crossshaft 34, As the cross shaft oscillates through the movements of thelink 39,- this arm 53 will be oscillated and this will in turn oscillatethe lever L19 carrying the thread hook '-17. rllhe thread linger 48isprovided with a shank 5a which is mounted in an arm carried by acollar 56. The collar 56 is clamped to a split sleeve 57 by a clampingscrew 58. The lever 49 swings freely on this collar. The specificmounting of the cross thread laying hook and the finger, forms no partof the present invention, but is shown, described and claimed in mycopending application, Serial Number 220,046, filed March 2, 1918. Thecross thread c passes through a thread guide 59 carried by the needleclamp 60 at the lower end of the need-le bar 5. This thread guide 59moves up and down with the needle bar. The cross thread c also passesthrough a tension 6l mounted on the ovei'- hanging arm. rlhe threadfinger a8 is shaped and positioned relative to the guide 59 so that whenthe guide is at the lower end of its stroke and the needles are cleardown, the cross thread will be moved forward on the finger andpositioned so that the thread hook as'it moves forward, will engage saidcross thread. As the hook continues its forward movement, thethreadguide 59 moves upwardly and the pull of the hook on the thread willcause the thread to slide back on the linfrer and be )ro erl Y)ositioned so that the needles 6 and 7 will straddle the thread thus the`cross thread is stitched to the fabric sections. This particularshaping of the thread linger and the relation of the same to the movablecross thread hook and the Vmovable thread guide on the needle bai', areshown, described and claimed in my copending application, Serial Number181,208, sied July is, i917;

A combined cover anddefiecting plate 62 is pivoted at 63 to an arm 64extending outwardly from thepi'esser foot and this cover plate 62 coversthe thread hook and extends across the movable trimming blade just in-rear of the pointof trimming, so that the trimmed off strip isdeflected away from the stitching mechanism.

From the above it will be noted that the movable trimming blade and 'thethread hook are both operated from a single eccentricand through aseries of levers'and connecting links, the proper timing and stroke ofthese devices are` obtained.

It is obvious that minor changes in the details of construction and thearrangement of parts, may be made without depart-ing from the spirit ofthe invention as set forth in the appended claims.

Having thus fully described my invention, what l claim is new and desireto secure by lLetters Patent is rl. A sewing machine including incombination, a standard, a cross shaft, a work sup-porting armprojecting from the standard, an overhanging aiin carried by thestandard, stitch forming` mechanism including a cross thread layingdevice, horizontally disposed trimming blades located in front of theAstitch forming mechanism, one of said blades being movable, aneccentric on the cross shaft, a rock shaft carried by the overhangingarm, means for oscillating thc rock shaft from said eccentric, an arm onsaid rock shaft and devices actuated thereby for oscillating said threadlaying device, and a second arm on said rock shaft and devices actuatedthereby for oscillating the movable triiinning blade.

2. A sewing machine includingl in combination a standard, a crosssha-ft, a work supporting arm projecting from the standard, anoverhanging arm carried by the standard, stitch forming mechanismincluding a cross thread laying device. horizontally disposed trimmingblades located in front of the stitch forming mechanism, one of saidblades being movable, an eccentric on the cross shaft, a rock shaftcarried by the overhanging arm, means for oscillating the rock shaftfrom said eccentric, an arm at one end of said rock shaft and devicesactuated thereby for oscillating said thread laying device, an arm atthe other end of said rock shaft and devices actuated thereby foroscillating the movable trimming blade.

3. A sewing machine including in combination a standard, a cross shaft,a work supporting arm projecting from the standard, an overhanging armcarried by the standard, stitch forming mechanism including a crossthread laying device, horizontally disposed trimming blades located infront of the stitch forming mechanism, one of said blades being movable,an eccentric on the cross shaft, a rock shaft carried by the overhangingarm at the forward end thereof, said rock shaft having an upwardlyextending arm, a lever carried by the standard at the rear end of theoverhanging arm, means Yconnected to the lower end of said lever foroscillating the same from said eccentric, a link for connecting theupper end of said lever with the arm projecting upwardly from the rockshaft and devices actuated by said rock shaft for oscillating the threadlaying device and for oscillating thc moi/'able trimming blade.

4. A sewing machine including in combination a standard, a cross shaft,a work supportingl arm projecting from the standard, anl overhanging armcarried by the standard, stitch forming mechanism includ- Ving a crossthread laying` device, horizontally disposed trimming blades located infront of the stitch forming mechanism, one of said blades being movable,an eccentric on the cross shaft, a rock shaft carriedby the overha-ngingarm at the florward end thereof, said rock shaft having an upwardlyextending arm, a lever carried by the standard at'the rear ends of theoverhangino' arm, means connected to the lower' end or said lever foroscillating t-he same from said eccentric, a link for connect-ino' theupper end of said lever with the armrpro- Yiecting upwardly 'from therock shaft, an

movable trimming blade for oscillating the same. Y Y

5. A sewing machine including in combination a' standard, a cylindricalwork sup porting arm ,projecting therefrom, an overhanging arm, meansfor iieeding, the material longitudinally of the arm, a presser foot, apresser bar supporting the same, a ixed horizontal trimming bladecarried by the presser foot, a movable horizontal trimming bladecoperating` with the fixed blade, a lever carrying -said movabletrimming blade, a bar mount-edler vertical movement in the head andconnected to the presser bar 'or supporting said lever, a lever mountedon the overhanging arm and having a link connection with the levercarrying'the trimming blade, a cross shaft in the standard and meansactuated by the cross shaft or oscillating the last named lever.

lnV testimony whereof, I aix my signa.- ture, in the presence of twoWitnesses.

JAMES R. MOFFATT.

lVitnesses i i S. lGrnonen Tarn, RALPH S. KnLso.

